[gtk+: 8/8] wayland: rework buffer management code (3 changes)

[Ray Strode <halfline src gnome org>]

commit 2ebae407ca743d09a82fd9a383b34779100c9fe6
Merge: 1cfa2f4 c80dd549
Author: Ray Strode <rstrode redhat com>
Date:   Sat Feb 6 08:03:27 2016 -0500

    wayland: rework buffer management code (3 changes)
    
    There are a couple of issues with the way that buffers are handled in
    wayland in right.  These issues mean that:
    
     - buffers can get leaked at a fairly fast clip under the right
       conditions. This leads to the OOM killer kicking in and
       gnome-shell and gnome-terminal (for instance) showing memory
       usage in the high gigabytes range.
    
     - drawing can happen to a shared memory buffer at the same time
       the compositor is reading out the pixels.  This can lead to
       glitching in drawing and other undefined behavior by the compositor.
    
    This changeset reworks how buffer management is done in the code to try
    to address both problems.
    
    The first change (commit 2c300081) addresses the leak by dropping code
    that has an unchecked cairo_surface_reference call.  The code is dropped
    rather than fixed, because it has a more serious issue: it's overarching
    purpose is to deal with shared memory buffer contention with the
    compositor, but it does it in a racy way and so fails at that mission.
    
    The second change (commit 40e91195a) moves what layer of the code buffer
    release events are handled. This is an organizational change in the
    code, with no functional changes, but it's important for the last change
    in the changeset.
    
    The last change (commit c80dd549) adds back code for dealing with shared
    member buffer contention in a race free way. The new code is careful to
    never reuse a buffer that hasn't been explicitly released by the
    compositor.

 gdk/wayland/gdkcursor-wayland.c  |   18 +++
 gdk/wayland/gdkdisplay-wayland.c |   33 ------
 gdk/wayland/gdkprivate-wayland.h |    2 -
 gdk/wayland/gdkwindow-wayland.c  |  214 +++++++++++++++++++++++++++++++-------
 4 files changed, 192 insertions(+), 75 deletions(-)
---